Telephone repeater



"April 9, 1929. w. WOLFF 1,708,748

TELEPHONE REPEATER Filed June 30, 1925 Fig.2.

6 5 Figi,

Tnventr: Walter Wofl FF,

His Attorney,

' 40 gized 5o effect the connection; As long Patented Apr. 9, 1929.

UNITED STATES PATENT OFFICE.

v WALTER WOLFE, OF BERLIN-KOPE1ICK,'GEBMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TELEPHONE REPEATER.

Application filed. June 30, 1925, Serial No. 40,564, and in Germany July 12, 1924.

My present invention relates to a switching system for automatically connecting a telephone repeater and balancing networks between two long distance telephone ofiices.

5 One of the objects of my invention isto provide an arrangement whereby a selector maybe operated in response to calling cur rent to automatically control the closing of a heating current for the repeatertubes and to automatically connect a calling and a called line to opposite sides of the repeater.

A further ob'ect of my invention is to provide means or openingthe heater circuit for the repeater tubes and for disconnecting the calling and called lines at the close of the conversation.

The novel features which I believe to be characteristic ofmy invention are set forth with particularity in the appended claims.

My invention itself, however, will best be understood by reference to the following description taken in connection with the accompanying drawing in which Fig. l-shows diagrammatically a tandem otfice V containing repeaters, and a plurality of stations 1-6 inclusive adapted to be connected to each other through ofiice V and an idle. repeater.

Fig. 2 shows diagrammatically a circuit organization whereby my invention may be carried into efi'ect.

Referring to the drawing, I have designated a calling transmission line as F, and the called transmission line as F,. Two relays as R, and R," are associated with each line, the former being used when a party at the end of the line is calling, and the latter relay being used when the party at the end of the line is called. Thus when line F is callin F, the relays R and R", are eneriy means of a selector and the lines F and F, are automatically connected across anam lifier of the repeater V. At the same time, t e lighting of the cathode element of the amplifying tube and the connection of 5 the compensating or artificial lines Kl and Kl, are effected by means of a selector 2. If other lines are to be connected with eachother, relays which I have indicated at R R, and R and R" 3 may be employed to as no impulses come over the line F,, the armature a, of relay G1,; is at rest so that none of the three selector arms 1", 7" and 1" can take up a connection andthe selector circuit is not energized unnecessarily. Each selector is provided with a disconnect relay Rwhich brings the selector arms back to the zero position at the end of the call. Relay R',.is equlpped with contacts 9,, 11 f 7: 1,, m while relay R, has contacts m,, 2,, 7a,, and

'z',. By means of these contacts, lines F and F,, and the balancing networks KZ and Kl, are connected. I

The method of operation is as follows: If line F is calling line F,, the operator at the end of line F may send four impulses. The relay Grl receives the four impulses and its armature a is brought up four times. This closes the circuit 0, the selector relay WR from the positive pole of battery B through armature a, and the winding of relay WR to the negative pole of the battery. The selector relay now rotates the selector arms from the position of rest 0 to position 4. In parallel with the relay WR is connected a slow release relay V,, which is energized at the same time that relay WR is energized, but whose armature releases only a short time after the succeeding impulses. The armature of relay V separates the two selector arms 1' and 1'" from the battery so that during the passing over of contacts 1-3 no false impulses of current result. After the release of the relayV current flows from the negative pole of battery B over the filaments of the amplifier tubes to the relay U, relay R",, line 92,, line y,, contact 7 ,,*arm 7', point 0 to the positive pole of battery B. This causes the armature of re lay R", to be attracted and to close a circuit from contact 8, through relays R' arm 7* and point 0, to the positive pole of the battery. Energization of relay R causes the tube circuit to be closed from the negative pole of battery B through the filaments of the tubes, relay U, relay R",, contact 8,, relay R contact b and contact '9 of the slow-acting relay ZR to the positive pole of the battery. The relay R moves its contacts 11,, k, to the active ositions g, and f also, the contacts Z and m, are thereby move'd into the active position. In this way the lineF and the balancing network connected through KZ,, are connected over the wires I and KZIV to the amplifier or repeater V. The same procedure is true for the relay R, which moves its contacts '21,, 1a,, Z, and m, intothe active position. This connects the line F, and the balancin network Kl, to the repeater over II and rest.

In this manner the tubes are lighted and the connection is completed and it is possible to talk, over the repeater. After the relay R,

has been operated, the release relay R rezero position. Relays R and R however remain connected to the battery B through contacts 6 and S4.

When talking is finished a signal is sent over the line F in order to disconnect the amplifier and lines. This current passes over contacts 9 and f, of relay R and over the lines I and amplifier V to the slow acting relay ZR. Energization of relay ZR opens the filament circuit at 9. At the same time relays R and R are deenergized so that their contacts return to the position of The system of relays is then again ready for taking up a new connection. If lines F and F 4 are connected, it is-impossible to connect either of these lines with another line. Thisis due to the fact that there are contacts 3 etc. on relay U for each line. When relay U is energized, these contacts disconnect the relay R from. the middle selector arms and complete a connection with the third selector arms r from battery B, contact 0 selector arm 7",

contact y of the called line, selector arm rf and relay ZR to the negative pole of the battery B. Energization of the relay ZR sends backin the customary manner a signal to the calling line and also brings the selector arms back to the zero position.

What I claim as new and desire tosecure by Letters Patent of the United States, is,

1. The combination in a telephone system of a plurality of transmission lines adapted tobe connected through a thermionic amplifier, an artificial line associated with each transmission line, and means responsive to a calling current for closing a heating circuit .ffor the amplifier cathode, and for connecting the artificial lines' with their associated transmission lines.

2. A signaling system comprising a plurality of stations, a transmitting line con nected to each station, a repeater adapted to be connected to said lines, said repeater comprising a thermionic amplifier, a plurality of relays associated with each transmitting line and adapted to connect that line tothe repeater, one of said relays being energized when the line is calling, and another being energized when the line is called, and means comprising a slow-acting relay for deenergizing said first mentioned relays when a conversation is ended.

3. The combination in a telephone system of a plurality of transmission lines adapted fier, 'means responsive to a calling current for closing a heating circuit for the amplifier cathode and also responsive to the same calling current for selectively connecting a calling station with any one of a'plurality of remote stations.

4. The combination in a telephone system of a plurality of transmission lines adapted tobe connected through a thermionic amplifier, means responsive to a calling current for closing a heating circuit for the amplifier cathode and also responsive to the same calling current for selectively connecting a calling station with any one of a plurality of remote stations, and means for preventing connection of a third transmission line with a busy line.-

5. A signaling system comprising a plurality of stations, a transmission line connected to each station, a repeater adapted to be connected to said lines, said repeater comprising a thermionic amplifier, a plurality of relays associated with each transmission line and adapted to connect the transmission line to opposite sides of. said repeater one of said relays being energized when the line is calling, and another of said relays being energized when the line is being called. v a

6. The combination in a telephone system of a plurality of transmission lines adapted to be connectedthrough a thermionic amplifier, a selector responsive to a'ealling 'cur-,

rent for closing a heating circuit for the amplifier cathode, and for selectively connecting'a callingstation with any one of a plurality of remote stations, and means for returing the selector to an inoperative position when the selection has been effected.

7. In combination a plurality of stations, transmissionlines "connected to said stations, a repeater adapted to be connected to said transmission lines, said repeater comprising" a thermionic amplifier, a plurality of relays associated with each line and a thermionic amplifier, a plurality o relays associated with each line and adapted to connect said lines with said repeater, a selector responsive to a calling current for efi'ecting operation of certain of said relays to connect -two of said transmissionlines to said repeater, and means for returing said selector to an inoperative position when the connection has been made without interrupting said connection.

9. In combination, a plurality of stations, transmission lines connected to said stations, a rcpeateradapted to be connected to said transmission lines, said repeater com rising a thermionic amplifier, a plurality o relays associated with each line and adapted to 10 connect said lines with said repeater, a

selector responsive to a calling current for effecting operation of certain of said relays to connect two of said transmission lines to saidrepeater, and means controlled by a relay associated with a calling line for returning said selector to an inoperative position.

In witness whereof, I have hereunto set my hand this 15th day of June, 1925.

WALTER WOLFF. 

